Tiled retroreflector with multi-stage dicing

Abstract

Methods of making tiled articles and molds used to make retroreflective articles. The methods include forming a prism array on a master substrate and forming a replica of the master. A reference edge is formed on the replica, thereby reducing the size of the prism array, yet maintaining a lateral dimension of the replica to maintain ease of handling of the replica. The replica is copied and the reference edge on the copied tiles are exposed, such that the reference edge can be mated and secured face-to-face with a reference edge on other tiles in order to form a tiled article. The tiled article is used as a mold to produce retroreflective articles or can be further duplicated and mated to form larger tiled articles to be used as molds. Tiled articles used as molds and retroreflective articles produced from the molds are also disclosed.

What is claimed is: 
     
       1. A method of making an article, the method comprising:
 forming prism elements on a first surface of a substrate; 
 forming a wall on the substrate, wherein the wall shares a first common edge with the first surface; and 
 forming a face on the substrate, wherein the wall shares a second common edge with the face, wherein the face shares a third common edge with a second surface of the substrate, and wherein the second surface is on an opposite side of the substrate from the first surface; 
 wherein the first common edge is on an opposite side of the wall from the second common edge, and wherein the third common edge is on an opposite side of the face from the second common edge. 
 
     
     
       2. The method according to  claim 1 , wherein an angle between the wall and the first surface is about 90° as measured through the substrate. 
     
     
       3. The method according to  claim 1 , wherein a height of the wall is greater than a height of the prism elements. 
     
     
       4. The method according to  claim 1 , wherein the wall is formed by making a depression in the substrate, the depression being at least partially defined by the wall. 
     
     
       5. The method according to  claim 4 , wherein making the depression includes removing a portion of the prism elements. 
     
     
       6. The method according to  claim 1 , wherein the wall is formed by diamond cutting. 
     
     
       7. The method according to  claim 1 , wherein:
 forming the wall comprises forming a plurality of walls; and 
 the prism elements are bounded by the plurality of walls. 
 
     
     
       8. The method according to  claim 7 , wherein:
 each of the plurality of walls shares a common interface with adjacent walls of the plurality of walls; and 
 depressions forming adjacent walls have different heights. 
 
     
     
       9. The method according to  claim 1 , wherein forming the wall on the substrate does not reduce a lateral dimension of the substrate. 
     
     
       10. The method according to  claim 1 , wherein the face is formed by removing a portion of the substrate. 
     
     
       11. The method according to  claim 10 , wherein removing a portion of the substrate includes removing a portion of the wall. 
     
     
       12. The method according to  claim 1 , wherein an angle between the face and the wall is less than 180° as measured through the substrate.